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Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - DRIVEN (Field driven materials for functions, dissipation, and mimicking Pavlovian adaptation)

Teaser

Summary

Biological materials have inspired materials scientists towards the design of new properties, e.g., for composites, photonics, and wetting. The future grand challenge is to mimic biological active materials integrating new properties that have not commonly been connected with man-made materials. This project addresses two challenges: 1) to develop field-driven dissipative out-of-equilibrium self-assemblies in the colloidal and molecular length scale, and 2) to develop materials whose responses are inspired by the simplest forms of learning, such as classic conditioning. Scientifically, progress in these fields will allow materials whose responses can adapt to new stimuli and undergo time-based programmable evolution. It is foreseen that they will allow conceptually new technologies for advanced materials and technological applications.

Work performed

At this stage of the project, two types of responsive material concepts inspired by classic (Pavlovian) conditioning have been shown. Minimally, classic conditioning needs responsivity to two stimuli and a triggerable memory to mediate their interplay. As the first model concept, we explored thermoreversible gels, where melting (response) takes place upon heating (unconditioned stimulus). The gel is conditioned to melt upon a specific light exposure (originally a neutral stimulus, becoming the conditioned stimulus), where the memory constitutes plasmonic nanoparticles whose assembly and optical response is triggerable by irradiation. The second concept deals with liquid crystalline elastomeric networks and their actuations. Heating (unconditioned stimulus) leads to bending. Upon conditioning by light irradiation (originally the neutral stimulus), the material acquires a new response to actuate even by light. As a sideproject, optically triggerable hydrophobization of a surface is shown. Zwitter-ionic liquid crystals are synthesized and their self-assembly is being investigated, aiming at electric field driven responses. Finally, cellulose nanocrystal/nanoparticle hybrids are synthesized and their functional behavior is studied.

Final results

We have demonstrated nonliving material systems that show elementary responses inspired by classic conditioning, showing qualitatively similar learning efficiencies vs. the mutual timings of the unconditioned and neutral stimuli as in biological conditioning. We show forgetting and extinction upon application of systems chemistry. Based on this initial success, we expect other schemes by the end of this project. Cellulose nanocrystal assemblies with nanoparticles allow new properties and assemblies upon imposed magnetic field and irradiation. These will be used for field-driven assemblies.